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[asan] Don't run stack malloc on functions containing inline assembly.

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It makes LLVM run out of registers even on 64-bit platforms. For example, the
following test case fails on darwin.

clang -cc1 -O0 -triple x86_64-apple-macosx10.10.0 -emit-obj -fsanitize=address -mstackrealign -o ~/tmp/ex.o -x c ex.c
error: inline assembly requires more registers than available

void TestInlineAssembly(const unsigned char *S, unsigned int pS, unsigned char *D, unsigned int pD, unsigned int h) {

unsigned int sr = 4, pDiffD = pD - 5;
unsigned int pDiffS = (pS << 1) - 5;
char flagSA = ((pS & 15) == 0),
flagDA = ((pD & 15) == 0);
asm volatile (
  "mov %0,  %%"PTR_REG("si")"\n"
  "mov %2,  %%"PTR_REG("cx")"\n"
  "mov %1,  %%"PTR_REG("di")"\n"
  "mov %8,  %%"PTR_REG("ax")"\n"
  :
  : "m" (S), "m" (D), "m" (pS), "m" (pDiffS), "m" (pDiffD), "m" (sr), "m" (flagSA), "m" (flagDA), "m" (h)
  : "%"PTR_REG("si"), "%"PTR_REG("di"), "%"PTR_REG("ax"), "%"PTR_REG("cx"), "%"PTR_REG("dx"), "memory"
);
}

http://reviews.llvm.org/D10719

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@240722 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Anna Zaks 2015-06-25 23:35:45 +00:00
parent a29c6d9ea6
commit f291e057a4
2 changed files with 59 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
lib/Transforms/Instrumentation/AddressSanitizer.cpp
View File

@ -1753,11 +1753,10 @@ void FunctionStackPoisoner::poisonStack() {
uint64_t LocalStackSize = L.FrameSize;
bool DoStackMalloc = ClUseAfterReturn && !ASan.CompileKernel &&
LocalStackSize <= kMaxStackMallocSize;
// Don't do dynamic alloca in presence of inline asm: too often it makes
// assumptions on which registers are available. Don't do stack malloc in the
// presence of inline asm on 32-bit platforms for the same reason.
// Don't do dynamic alloca or stack malloc in presence of inline asm:
// too often it makes assumptions on which registers are available.
bool DoDynamicAlloca = ClDynamicAllocaStack && !HasNonEmptyInlineAsm;
DoStackMalloc &= !HasNonEmptyInlineAsm || ASan.LongSize != 32;
DoStackMalloc &= !HasNonEmptyInlineAsm;
Value *StaticAlloca =
DoDynamicAlloca ? nullptr : createAllocaForLayout(IRB, L, false);

56
test/Instrumentation/AddressSanitizer/X86/asm_more_registers_than_available.ll Normal file
View File

@ -0,0 +1,56 @@
; RUN: opt < %s -asan -S -o %t.ll
; RUN: FileCheck %s < %t.ll
; Don't do stack malloc on functions containing inline assembly on 64-bit
; platforms. It makes LLVM run out of registers.
; CHECK-LABEL: define void @TestAbsenceOfStackMalloc(i8* %S, i32 %pS, i8* %D, i32 %pD, i32 %h)
; CHECK: %MyAlloca
; CHECK-NOT: call {{.*}} @__asan_stack_malloc
target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-apple-macosx10.10.0"
define void @TestAbsenceOfStackMalloc(i8* %S, i32 %pS, i8* %D, i32 %pD, i32 %h) #0 {
entry:
%S.addr = alloca i8*, align 8
%pS.addr = alloca i32, align 4
%D.addr = alloca i8*, align 8
%pD.addr = alloca i32, align 4
%h.addr = alloca i32, align 4
%sr = alloca i32, align 4
%pDiffD = alloca i32, align 4
%pDiffS = alloca i32, align 4
%flagSA = alloca i8, align 1
%flagDA = alloca i8, align 1
store i8* %S, i8** %S.addr, align 8
store i32 %pS, i32* %pS.addr, align 4
store i8* %D, i8** %D.addr, align 8
store i32 %pD, i32* %pD.addr, align 4
store i32 %h, i32* %h.addr, align 4
store i32 4, i32* %sr, align 4
%0 = load i32, i32* %pD.addr, align 4
%sub = sub i32 %0, 5
store i32 %sub, i32* %pDiffD, align 4
%1 = load i32, i32* %pS.addr, align 4
%shl = shl i32 %1, 1
%sub1 = sub i32 %shl, 5
store i32 %sub1, i32* %pDiffS, align 4
%2 = load i32, i32* %pS.addr, align 4
%and = and i32 %2, 15
%cmp = icmp eq i32 %and, 0
%conv = zext i1 %cmp to i32
%conv2 = trunc i32 %conv to i8
store i8 %conv2, i8* %flagSA, align 1
%3 = load i32, i32* %pD.addr, align 4
%and3 = and i32 %3, 15
%cmp4 = icmp eq i32 %and3, 0
%conv5 = zext i1 %cmp4 to i32
%conv6 = trunc i32 %conv5 to i8
store i8 %conv6, i8* %flagDA, align 1
call void asm sideeffect "mov\09\09\09$0,\09\09\09\09\09\09\09\09\09\09%rsi\0Amov\09\09\09$2,\09\09\09\09\09\09\09\09\09\09%rcx\0Amov\09\09\09$1,\09\09\09\09\09\09\09\09\09\09%rdi\0Amov\09\09\09$8,\09\09\09\09\09\09\09\09\09\09%rax\0A", "*m,*m,*m,*m,*m,*m,*m,*m,*m,~{rsi},~{rdi},~{rax},~{rcx},~{rdx},~{memory},~{dirflag},~{fpsr},~{flags}"(i8** %S.addr, i8** %D.addr, i32* %pS.addr, i32* %pDiffS, i32* %pDiffD, i32* %sr, i8* %flagSA, i8* %flagDA, i32* %h.addr) #1
ret void
}
attributes #0 = { nounwind sanitize_address }
attributes #1 = { nounwind }